This invention relates generally to an apparatus for measuring the level of gaseous pollutants in the crankcase of an internal combustion engine. More particularly, the apparatus continuously separates particulates and lubricating oil from crankcase gas to facilitate measuring gaseous pollutants of interest.
Designers of internal combustion engines strive to reduce levels of pollutants generated in the engine. One carrier of pollutants is blow-by gas in the crankcase. This gas is typically recirculated by a Positive Crankcase Ventilation (PCV) system into the intake manifold of the engine where the gas flows into the combustion chamber to be burned. In order to optimize the design of the PCV system, it is desirable to measure, in real time, the level of pollutants in the blow-by gas. Once the level of pollutants is known it is possible to make changes to the engine control system, engine components and the PCV system to reduce pollutant levels.
One method of indirectly measuring pollutant levels is to perform a spectral analysis of oil used in the engine. With this method, the engine is operated under a prescribed operating condition for a specified period. At the end of the period, a sample of the engine oil is subjected to a spectral analysis that exposes the level of contaminants in the oil. The pollutant level in the blow-by gas is then inferred from the results of the spectral analysis and knowledge of the prescribed operating condition to which the engine was subjected. While the spectral analysis test is used by engine designers, it has two shortcomings. The first shortcoming is the time needed to produce measurements of pollutant levels. A typical specified period can be 10,000 miles of operation in an automobile. With such a long test period, engine designers are limited to running a few tests before an engine design must be ready for production. Second, the spectral analysis test only provides indirect information on the aggregate level of pollutant levels in the blow-by gas. The test does not provide pollutant levels as a function of time. This leaves the engine designer guessing what mode of engine operation produces the worst pollutant level.
Accordingly, one aspect of this invention is to provide a system for facilitating measurement of pollutant levels in the crankcase gas of a running engine.
In accordance with this aspect, the present invention provides a gas separator system for providing contaminant-free engine crankcase gas to a gas analyzer. The system has an inlet member for receiving the crankcase gas from the engine and an oil separator for separating at least a portion of the contaminants from the crankcase gas. A pump is arranged to draw the crankcase gas through the inlet member and move the separated crankcase gas to the gas analyzer.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.